Structures Laboratory, U.S. Army Research and Technology Laboratories (AVSCOM), NASA Langley Research Center, Hampton, VA
Pages: 16 Published: Jan 1985
An equation was derived for the strain-energy release rate, G, associated with local delamination growth from a matrix ply crack. The critical Gc for edge delamination onset in [±25/902]s graphite/epoxy laminates was measured and used in this equation to predict local delamination onset strains in [±25/90n]s, where n = 4, 6, 8 laminates. A simple technique for predicting strain concentrations in the primary load bearing plies near local delaminations was developed. These strain concentrations were responsible for reduced laminate nominal failure strains in laminates containing local delaminations. The influences of edge delamination and matrix crack tip delamination on laminate stiffness and strength were compared.
graphite/epoxy materials, delamination, matrix ply cracks, strain concentration, strain-energy release rate, fatigue, composite materials, interlaminar fracture
Paper ID: STP36310S